Answer: Nine: two parents, 6 sisters and a younger sister 

`text(Since humans produce offspring through the mating of male and since the parent have children)`

`text(Number of parent = 2      (1))`

`text(Number of sons/brothers including yourself = 6   (2))`

`text(Number of sisters each son has = 1)`

`text(Therefore, number of daughter parents have = 1  (3))`

(-> (1) + (2) + (3) gives the number of people in the family)

`text(Therefore, the total number of in the family is)`

`text(<-> 2 + 6 + 1 = 9)`

`text(-> The answer is: 9)`

`text(@NoCopy!)`